Symptomatology and allergen types in patients presenting with allergic rhinitis

Allergic rhinitis, despite its complex patho-physiology, is a global health problem with the increasing prevalence. The current study which was conducted at one of the tertiary care center in the country comprised of 548 diagnosed cases of allergic rhinitis and thus treated during the period extending from January 2010 to June 2011. In the study, males and females were almost equally distributed, constituting the ratio of 1:0.9. Among them, the patients from 20 –29 year of age group was the most commonly affected (38.1%). In our study most of the patients were housewives (30.3%) and the house dusts mites (76.3%), was the most common etiological factors. Majority of the patients presented with sneezing (86.7%) as the chief complaint. Of the total subjects, 18.6% presented with co-morbidity of allergic conjunctivitis and 8.9% with that of sinusitis.


Introduction:
Allergic rhinitis (AR) is a very common disease, affecting 10-20% of the population world wide 1 .AR is an IgE mediated immunological response of nasal mucosa to allergens and is characterized by sneezing, watery nasal discharge, nasal obstruction and itching in the nose.Two clinical types have been recognized, seasonal and perennial.Allergic rhinitis is a global health problem and is increasing in prevalence.The pathophysiology of allergic rhinitis is complex, involving cells, mediators, cytokines, chemokines, and adhesion molecules which co-operate in a complex network to produce the specific symptoms of allergic rhinitis and the nonspecific hyperactivity.The reaction can be considered in four phases: Sensitization, Subsequent reaction to allergen early phase, Late phase reaction and Systemic activation.Allergens provoke production of IgE antibodies in the genetically predisposed individuals.These antibodies become fixed to the mast cells or basophils by its Fc end.On subsequent exposure, antigen combines with IgE antibody.This reaction produces degranulation of mast cells with release of chemical mediators.The increased number of degranulating mast cells in the nasal epithelium produces significant vascular leakage and interstitial edema resulting in irritation of sensory nerves, nasal pruritis, rhinorrhoea, nasal congestion and sneezing.The late phase immune response occurring in approximately half of exposed patients, involves the ingress of eosinophils, basophils, mast cells, T-lymphocytes, neutrophils, and macrophage into local tissues, all of which contribute to the inflammatory response which present as nasal obstruction and hyperactivity.
Mites living in the dust of house are called house dust mites and they are the known causative agents in the development of respiratory allergies all over the world.The respiratory allergies are caused by the inhalation of dead or live mites, their faecal matter or other byproducts.House dust mites are 8-legged minute, 0.2 to 0.4 mm in size.In houses they feed exclusively on human dander or dead skin that an adult human sheds.Within a house, the dust in mattresses, carpets, corners of rooms and floor space beneath the bed provide the most favourable niches.The bed is the most intimate.The commonest species of dust mite is Dermatophagoides pteronyssinus 2 .
Pollen from trees, grasses and weeds can be inhaled, and cause allergic symptoms.Pollen may travel many miles in the wind.Therefore, trees, grasses and weeds in your general area can cause allergic symptoms.Pollen allergies are often seasonal.Allergy symptoms occur when the amount of pollen is present in air.Pollens from trees tend to be highest in the spring.Pollens from grasses tend to be highest in the summer, but are present almost all year round especially in some parts of the country.Pollens from weeds tend to be highest in the summer.This may vary depending on weather conditions and where one lives.
Allergic rhinitis, an allergen-induced inflammation of the nasal mucosa, is frequently associated with co-morbid conditions.Co-morbidity refers to the association between AR and other diseases like allergic conjunctivitis, bronchial asthma, sinusitis, nasal polyp, chronic pharyngitis, otitis media with effusion and chronic suppurative otitis media.The mucosa lining the upper and the lower respiratory tracts are continuous and are governed by similar genetic, immunologic and environmental factors, resulting in similar inflammatory and immune responses.The two conditions may manifest together or sequentially.The management algorithm of allergic rhinitis is dependent on the identification of the etiologic allergen and symptom severity.The type of allergens, however, differs widely depending on localities 3,4 .An acute attack of allergic rhinitis may precipitate acute attacks of bronchial asthma as shown in Eastern India 5 .Allergic rhinitis is a known risk factor for later development of asthma and treating allergic rhinitis has been shown to improve asthma symptoms 6,7 .

Methods:
This is a prospective hospital based study conducted at Department of ENT -Head & Neck Surgery, Gandaki Medical College Charak Hospital, Pokhara, Nepal between January 2010 to June 2011.All patients attending ENT clinic and seen by ENT surgeons, clinically diagnosed as allergic rhinitis and both sexes irrespective of age were enrolled in the study.Diagnosis was made on the basis of history and physical examination.A detailed history was taken regarding symptoms of allergic rhinitis.Presence of pale or blue nasal mucosa and hypertrophied boggy turbinate and watery nasal discharge was considered in diagnosing the allergic rhinitis.Additional investigation skin prick allergy testing, x-ray paranasal sinuses and CT-paranasal sinuses were done.The information included demographic data like age, sex, profession and history of ENT disease, duration of complaint and physical examination was noted.Allergic study was conducted by the consultant dermatologist after the ethical consideration and consent.The tests were performed according to standard methods with allergens, histamine -positive and histaminenegative controls purchased from ALK-Abello (Denmark).The allergens used were mites, fungi, dusts, pollens, epithelia, insects and foods.The skin prick reaction wheal diameter was at least 3mm larger than the negative control.Patients who were already on antihistamine and steroids were excluded from the study.

Results:
In this study involved 548 patients Male 279(50.9%)and female 269(49.1%),male female ratio was 1:0.9, mean age of 30.9 years (SD-12.4)with range from 5 years to 81 years.The age distribution of the study population is shown in Table1.The majority of patients of our study present with the complaints of sneezing (86.7%), rhinorrhoea (69.9%), itching nose (58.0%) and nasal obstruction (53.8%)., including asthma 13,14 .We have seen that allergic conjunctivitis (18.6%) is the common co-morbid condition similar to other study which showed allergic conjunctivitis (13%) 15 and sinusitis (8.9%) is of the second in percentage.Allergic rhinitis is a known risk factor for later development of asthma and treating allergic rhinitis has been shown to improve asthma symptoms 16,17 .A series reported that 58.8% of patients with AR had findings consistent with asthma 18 .Different study performed in Turkey report frequencies of 7.5% to 14.7% for asthma, [19][20]

Conclusion:
Early diagnosis and proper treatment of allergic rhinitis help reduce school or work absence, morbidity and complications.Awareness of associated co-morbid conditions is also important in the workup and complete treatment, of allergic rhinitis.Allergy testing plays a key role in identification of allergen which is a viable alternative to medical management by avoiding the allergen.

Table - I
Age distribution (n=548) while our study reveals that patient with asthma were only 9.7%, which is not in same correlation with other series but same in findings with studies done in Turkey.We establish our diagnosis by history, clinical examination and investigations.Allergy test and CT-PNS were least done because of cost effect .Allergy test facilities are not available in any government hospitals.IgE estimation, Allergy tests are expensive and are performed only in some private centers.Majority of our patients can't afford these costly tests.Moreover, people are reluctant to do laboratory tests for allergic diseases except in severe cases.We have done allergic test, x-ray paranasal sinus and CT-scan paranasal sinuses.